JP5754081B2 - Sand collection device for sand basin - Google Patents

Description

The present invention relates to a sand collecting method and a sand collecting apparatus for collecting earth and sand precipitated in a sand basin of a sewage treatment facility in a sand collecting pit.

With the water in the settling basin drained (drained), low pressure water of less than 3 kg / cm ² is sprayed from the nozzle installed in the settling basin to the bottom of the settling basin, and the sediment deposited on the bottom of the settling basin is washed away. The low-pressure sand collection device that collects in the sand collection pit provided in the center of the bottom of the pond and the sand collected in the sand collection pit are pumped together with water by the sand pump installed in the sand collection pit and transferred to the sewage sedimentation basin. A sand removal apparatus is disclosed in Patent Document 1.

  The nozzle near the side wall of the sand settling basin in the low pressure sand collecting type sand collecting device is a nozzle installed near the side wall of the settling basin for each region obtained by dividing the bottom surface of the sand settling basin into the direction of water flow in the settling basin. A plurality of headers are attached at equal intervals.

By the way, the bottom surface of the sand basin has an inclination angle of 5-7 degrees with respect to the horizontal plane toward the center of the bottom of the sand basin. And the nozzle of the conventional nozzle header is attached so that the incident angle (theta) with respect to the bottom of the settling basin of the nozzle of the nozzle may be less than 45, as FIG. 15 shows.

Japanese Patent No. 3315489

  The amount of sediment deposited on the bottom surface of the sand basin is the largest in the region near the side wall W of the bottom surface 2a. However, as described above, the nozzle of the conventional nozzle header has an incident angle with respect to the bottom surface of the settling basin of less than 45 degrees, so that all the water sprayed from the nozzle and landing on the bottom surface of the settling basin Since it flows to the trough 8a side, the earth and sand that flows effectively by the water discharged from the nozzle is limited to the range from the landing position of the bottom of the settling basin of the discharged water from the nozzle to the trough 8a side, and from the landing position to the side wall There has been a problem that the sediment S having the largest amount of deposit may remain without being washed away.

The present invention has been made in view of the above circumstances, in a sand collection device for a sand basin provided with a nozzle for injecting low pressure water to the bottom surface of the sand basin and flowing earth and sand accumulated on the bottom surface, It is an object of the present invention to provide a sand collection method and a sand collection device for a sand basin which can efficiently flow earth and sand accumulated on the bottom of the sand basin to a trough without remaining in the vicinity of the side wall of the sand basin.

The present invention, in order to achieve the above object, the sediment by injecting low pressure water to the bottom surface of the nozzle or al-precipitated sand basin is deposited on its bottom surface to flow into the main trough, the main runner sediment the sand basin in collecting sand method of the low-pressure collecting sand method to collect the collecting sand pit provided in the bottom, and placing the nozzle near the top of the side wall of the settling pond, located above the water surface of the sand basin the nozzle sand basin as waste state after the water from the nozzle is injected into the upper portion of the wall surface of the side wall, as well as washing the walls, directed the sediment deposited on the bottom surface of the sand basin by the water flowing down the wall to the main trough It is characterized by flowing .
Another feature of the present invention is that the discharge amount of the nozzle is 0.15 to 0.3 m ³ / min.

In order to achieve the above object, the present invention jets low-pressure water from a nozzle to the bottom surface of a drained sedimentation basin and causes the sediment deposited on the bottom surface to flow into the main trough. In the low-pressure sand collection device that collects in the sand collection pit provided at the bottom of the basin, the bottom of the sedimentation basin is divided into a plurality of areas in the direction of the water flow in the sedimentation basin. The nozzle attached in (1) is attached so that water sprayed from the nozzle is jetted at an incident angle of 15 to 60 degrees with respect to the upper wall surface of the side wall .

According to the present invention , dirt attached to the wall surface can be removed. The jet water from the nozzles vigorously flows down along the wall surface of the side wall using potential energy, so that not only the wall surface can be cleaned but also the earth and sand can be washed away from the position near the side wall of the bottom surface. Even when the sand basin is not drained, the nozzle can be prevented from being immersed in the sewage, so that it is possible to avoid contamination of the nozzle, particularly in the head. In addition, water sprayed from the nozzle flows from the upper part to the lower end of the side wall of the sand basin, and further flows through the bottom surface of the sand basin, so that the sand does not remain on the side wall portion of the bottom of the sand basin. You can collect all the sediment that has accumulated on the bottom of the pond. When the spray water is sprayed at an incident angle of 15-60 degrees with respect to the upper wall surface of the side wall, the water sprayed from the nozzle can flow down along the wall surface without splashing away from the side wall. As a result, the wall cleaning effect is improved.

It is a longitudinal cross-sectional view of the rainwater treatment facility including a sand basin. FIG. 2 is a partially omitted plan view of the range of line XX in FIG. 1. FIG. 3 is a cross-sectional view taken along line Y1-Y1 of FIG. FIG. 3 is a sectional view taken along line Y2-Y2 of FIG. FIG. 3 is a cross-sectional view taken along line Y3-Y3 of FIG. It is a water supply system diagram. It is a front view of a nozzle header. It is sectional drawing which shows the attachment state with respect to the sand basin of a nozzle header. It is an enlarged view which shows the structural example of the nozzle of a nozzle header. It is a figure explaining the control apparatus of a sand collecting apparatus. It is explanatory drawing of a water level sensor. It is a flowchart figure of a sand pump control means. It is a flowchart figure of a switching valve control means. It is sectional drawing which shows other embodiment of this invention. It is a figure which shows the attachment state of the nozzle in the conventional sand collecting apparatus.

Next, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a rainwater treatment facility, which includes a sand basin 2 and a pump well 3 formed between side walls Wa and Wb (see FIG. 2). The settling basin 2 is connected to an inflow trough 4 from which sewage such as rainwater and sewage is collected from a sewage pipe not shown. A dam device 5 for allowing or preventing the inflow of sewage from the inflow trough 4 to the sand basin 2 is installed at the downstream end of the inflow trough 4. A contaminant capturing screen 6 is installed immediately before the upstream end of the screen.

  As described above, the bottom surface 2a of the sand basin 2 is inclined so that the center is the deepest, and a sand collection pit 7 is formed at the center, and at the bottom of the sand basin, The main trough 8a is formed between the side walls Wa and Wb so that the sand collecting pit side is deep in parallel with the water flow direction in the sand basin, and the surface is inclined downward from the lower end portions of the side walls Wa and Wb to the sand collecting pit 7 (hereinafter referred to as the sand collecting pit 7). 8b is formed, and a number of small troughs 8c extending in the direction perpendicular to the water flow direction in the sand basin from the vicinity of the side walls Wa and Wb to the main trough 8a are formed on the bottom surface of the sand basin. ing.

  Moreover, in order to reduce the burden of the water supply pump P2 and the sand pump P3 which will be described later, the bottom surface of the sand basin is divided into a plurality of regions in the direction of the water flow in the sand basin on both sides of the main trough 8a. In the example of FIG.2 and FIG.8, it divides into 8 area | regions B1-B8. Depending on the size or width of the sand basin, the main trough 8a may be formed at a position near one side wall.

  Moreover, the nozzle 9a is installed in the upper end part of the main trough 8a, and the upper end part of the sand collection pit inclined surface 8b, and many nozzles 9b are installed along the side walls Wa and Wb of each area | region B1-B8. Further, a nozzle 9 c for stirring the collected earth and sand is installed in the sand collecting pit 7.

  A plurality of nozzles 9b installed in the regions B1 to B8 are attached at equal intervals to the nozzle header NH installed in the vicinity of the side walls Wa and Wb of the regions B1 to B8. FIG. 7 shows an example of a nozzle header NH configured by attaching eight nozzles 9b at equal intervals of 500 mm to a mother pipe 11 having a length of 4200 mm having the branch pipe 10.

  And as shown in FIG. 8, the nozzle 9b of the nozzle header NH is about 1500 mm from the highest position on the bottom surface of the sand basin, for example, above the normal water surface when sewage is stored in the sand basin. It is attached to the side wall W so as to inject water downward. The distance D from the tip center of the nozzle 9b to the side wall W is 150 to 400 mm. As an example, the pressure of water sprayed from one nozzle is 0.005 MPa, and the discharge rate is 150 liters / minute. When the nozzle 9b of the nozzle header NH is provided above the normal water surface, there is an advantage that dirt attached to the side wall W can be removed by the jet water.

  In a preferred embodiment of the present invention, the effective injection force of the nozzle 9b is obtained while ensuring the distance from the side wall W of the nozzle header NH so that the nozzle header NH can be easily attached. Nozzle 9b having a specific structure as shown in FIG.

  That is, the nozzle 9b is composed of a straight base tube (A), a 45 ° elbow (B), and a nozzle head (C), and one end of the 45 ° elbow (B) is a base tube (I). ) And the other end are connected to the base end of the nozzle head (c) by screwing.

  The reason for using the 45-degree elbow (b) and nozzle head (c) coupled by screwing is that the nozzle head (c) used in the present invention has a caliber depending on the discharge pressure of the feed pump or the discharge speed required for the nozzle head. Alternatively, it may be necessary to change to a different mouth shape, so that the exchange is possible. Therefore, according to this embodiment, even when the spraying conditions are different, it is possible to efficiently collect sand without replacing the sediment on the side wall of the bottom surface of the sand basin by simply replacing the nozzle head (c). Can be realized.

  In the pump well 3, a drainage pump P 1 and a water supply pump P 2 that also serves as a staying water pump are installed, and a sand pump P 3 is installed in the sand collecting pit 7. F of FIG. 1 is a filter installed at the downstream end of the sand basin 2.

  As illustrated in FIGS. 5 and 6, the water from the water supply pump P <b> 2 of the pump well 3 is supplied to the nozzles 9 a, 9 b and 9 c (water passing), or the supply is stopped (water stopping). Switching valve groups VG1 and VG2 constituted by electromagnetic valves, that is, a trough switching valve Va, each nozzle header switching valve Vb, and a sediment agitation nozzle switching valve Vc are provided. These switching valves Va, Vb1 to Vb8, and the stirring nozzle switching valve Vc are configured to be switched to a water flow state or a water stop state in a predetermined order by a switching valve control means described later.

  Relief means 12 is provided via a switching valve Vd in the pipeline connecting the water supply pump P2 and the switching valve groups VG1, VG2, and water from the water supply pump P2 when all the switching valves are closed is supplied. It is configured to escape to the sand basin 2.

  As illustrated in FIG. 10, an operation panel 101 having a sand removal start button (not shown) is added to the control device 100 provided in the sand collecting device according to the above embodiment, and the drain pump control means PCON1. The feed water pump control means PCON2 and the sand pump control means PCON3 are incorporated, and the switching valve control means VCON is incorporated. As will be described later, the switching valve control means VCON gives a control signal for driving the group of switching valves Va, Vb, Vc, Vd to open or close in a predetermined order.

  Further, the control device 100 is installed in the sand collecting pit 7, and the water level in the sand collecting pit 7 is higher than a predetermined high water level HWL conceptually shown in FIG. 11, any of the intermediate water level MWL and the low water level LWL. A water level sensor 15 that detects and outputs whether or not there is an electrical connection is electrically connected.

  Going forward, the operation of the above configuration will be described for the case where there are four sand basin regions. When the dam device 5 is opened, the sewage flows into the sand basin 2 and further into the pump well 3, and when the water level reaches a predetermined height, the drain pump control means of the control device 100 of the sand removal device. The drain pump P1 provided in the pump well 3 is operated by PCON1, and the water in the pump well 3 is pumped up and transferred to a terminal treatment plant or the like outside the figure.

  During the transfer, earth and sand are precipitated from the sewage mixed with the earth and sand flowing into the sand basin 2 and deposited on the bottom surface 2a of the sand basin. When the accumulation amount reaches a predetermined value, the dam device 5 is closed and the inflow of sewage into the sand basin 2 is prevented. And when the water level of the sand basin 2 and the pump well 3 is lowered by the drainage by the drainage pump P1, and reaches a predetermined water level (WL in FIG. 1) equal to the upper surface of the weir provided between the sand basin 2 and the pump well 3. The operation of the drainage pump P1 is stopped by the drainage pump control means PCON1.

  When it is detected that the water level of the pump well 3 has reached a predetermined water level (WL in FIG. 1), the control device 100 activates the feed water pump control means PCON2, the sand pump control means PCON3, and the switching valve control means VCON.

  As shown in FIG. 12, the sand pump control means PCON3 starts the automatic operation mode of the sand pump P3 (S11), and the water level in the sand collecting pit 7 is set to a predetermined high water level by the detection signal from the water level sensor 15. It is checked whether or not it is equal to or higher than HWL (S12).

  Further, as shown in FIG. 13, the switching valve control means VCON first opens the switching valve Vd of the relief means 12 and prepares to drive the water supply pump P2 (step S21 in FIG. 13). Subsequently, after the nozzle switching valve Va is opened (S22), the switching valve Vd of the relief means 12 is closed (S23), so that water from the water supply pump P2 flows from the nozzle 9a to the main trough 8a and sand collecting pit inclined surface 8b. Is erupted. Thereby, the earth and sand in each trough is poured toward the sand collection pit 7 with water.

  Since the discharge amount of the sand pump P3 is larger than the discharge amount of the water supply pump P2, the water level in the sand collecting pit 7 is lowered. When the water level sensor 15 detects that the water surface has reached a predetermined intermediate water level (Y in S24), the switching valve control means VCON opens the nozzle header switching valve Vb1 in the first region B1 (S25). Therefore, water is jetted from each nozzle of the nozzle header, and the earth and sand accumulated in the first region B1 is flowed toward the main trough and further flows into the sand collecting pit 7. Thus, the sewage mixed with the earth and sand collected and stirred in the sand collecting pit 7 is pumped up by the sand pump P3 and transferred to the earth and sand basin. Thereby, although the water surface in the sand collection pit 7 rises temporarily, it falls in time.

  When the water level sensor 15 detects that the water surface has again reached the predetermined intermediate water level (Y in S26), the switching valve control means VCON closes the nozzle header switching valve Vb1 in the first region B1. In order to open the nozzle header switching valve Vb2 in the second area B2 (S27), water is sprayed from each nozzle of the nozzle header, and the earth and sand accumulated in the second area B2 is flowed toward the main trough. Furthermore, it flows into the sand collecting pit 7.

  Accordingly, as in the case of the first region, the water surface in the sand collecting pit 7 temporarily rises but then drops, so when the water surface reaches a predetermined intermediate water level (Y in S28), The switching valve control means VCON closes the nozzle header switching valve Vb2 in the next second region B2, and further opens the nozzle header switching valve Vb3 in the next third region B3 (S29). Water is jetted from each nozzle.

  Accordingly, as in the case of the first region, the water level in the sand collecting pit 7 temporarily rises but then drops, so when the water level reaches a predetermined intermediate water level (Y in S210), The switching valve control means VCON closes the nozzle header switching valve Vb3 in the third region B3 and opens the nozzle header switching valve Vb4 in the fourth region B4 (S211), so that water is injected from each nozzle of the nozzle header. Is done.

  Accordingly, as in the case of the first region, the water level in the sand collecting pit 7 temporarily rises but then decreases, so when the water level reaches a predetermined intermediate water level (Y in S212), The switching valve control means VCON determines that the water injection to the fourth area B4, that is, the last area has ended, opens the relief valve switching valve Vd, and switches the nozzle header switching valve Vb4 in the fourth area B4. Is performed to complete a series of switching valve controls. Also, the feed water pump control means PCON2 stops the operation of the feed water pump P2.

  On the other hand, the sand pump control means PCON3 constantly monitors the detection state of the water level sensor 15 from the start of the operation of the sand pump P3, and by closing the nozzle header switching valve Vb4 in the fourth region B4, Since the water level in the sand pit 7 falls to the low water level LWL (when S14 is Y), the operation of the sand pump P3 is stopped (S15). Thereafter, the sand pump control means PCON3 checks whether or not the control of the switching valve has been completed (S16). If it has not been completed, the process returns to step S12, and the water level becomes high (when S12 is Y). Starts the operation of the sand pump P3 again, but after confirming the completion of the switching valve control (Y in S16), cancels the automatic operation mode of the sand pump (S16).

  As described above, when starting the automatic operation mode, the sand pump P3 is automatically activated when the water level in the sand collection pit is above a predetermined high water level HWL in order to maintain the sand collection pit 7 in a drained state. However, in this embodiment, the water surface in the sand collection pit has a predetermined high water level HWL and a predetermined water level when the water level drops to a predetermined low water level LWL. When the water level drops to the intermediate water level MWL during the low water level LWL, the nozzle header switching valve in the first order region is closed and the nozzle header switching valve in the second order region is opened. During this period, the water level in the sand collection pit is stopped by the closing operation of the nozzle header switching valve in the first order area, pumping up the sand pump, and opening the nozzle header switching valve in the second order area. Of water injection by Although it varies depending on the start, the intermediate water level, which is a temporal reference for the switching operation of the switching valve, may be set to a height position where the water level in the sand collecting pit does not drop to a predetermined low water level during the switching operation of the switching valve. . The height position can be calculated from the injection amount of each nozzle and each nozzle header, the cross-sectional area of the sand collecting pond, the discharge amount of the sand pump, and the like.

As described above, the nozzle 9b of the nozzle header in any of the above regions injects water at a pressure of 0.005 MPa toward the side wall W at a water amount of 0.15 m ³ / min per nozzle in the drainage state of the sand basin. However, since it is injected at a low pressure, the water that has landed on the upper part of the wall surface spreads on the wall surface and then flows down to the lower end of the wall surface. At this time, water flows down vigorously using the potential energy by spraying water onto the upper part of the wall surface. Therefore, the wall surface can be cleaned by flowing the deposits on the side wall. The sewage that reaches the end of the bottom of the sand basin causes the sediment deposited on the bottom to flow through the trough. Therefore, the water from all the nozzles 9b of each nozzle header can efficiently collect sand in the sand collecting pit without leaving the earth and sand on the entire side wall and bottom surface.

  Since water sprayed from one nozzle at a low pressure spreads on the wall surface of the side wall W, the nozzle mounting pitch of the nozzle header can be larger than the conventional 400 to 500 mm, for example, 750 mm. Therefore, the number of nozzles per area can be reduced.

In order to cause water sprayed from the nozzle 9b to flow down along the wall surface without splashing back in the direction away from the side wall W, the incident angle (θ1 in FIG. 8) of the spray center line from the nozzle with respect to the inner surface of the side wall is set to 15 It is desirable to set in a range of ˜60 degrees. The discharge rate from the nozzle 9b can be 0.15 to 0.3 m ³ / min, preferably 0.15 to 0.2 m ³ / min. In addition, the effective range of the inclination angle ((theta) 2 of FIG. 8) with respect to the horizontal surface of the bottom face 2a of a sand basin is 5-33 degree | times, and a suitable range is 7-15 degree | times.

  In the case of the embodiment shown in FIG. 9, since the nozzle 9b is installed at a high position, the spray water from the nozzle vigorously flows down along the wall surface of the side wall W using the potential energy. Not only can dirt be washed, but also the advantage that earth and sand can be washed away from the position close to the side wall of the bottom surface 2a, and the nozzle 9b can be prevented from being immersed in sewage even when the sand basin is not drained. In particular, it is possible to avoid contamination of the head.

  However, it is not necessary to limit the installation position of the nozzle 9b to a high place, and as illustrated in FIG. You may make it make it. In this case, the jet water rebounds vigorously from the side wall W to the bottom surface 2a, so that it is possible to run away without leaving earth and sand anywhere on the bottom surface.

DESCRIPTION OF SYMBOLS 1 Rainwater treatment facility 2 Sand basin 3 Pump well 5 Dam device 7 Sand collection pit 8a Main trough 8b Sand collection pit inclined surface 8c Small trough 9a Trough nozzle NH Nozzle header 9b Nozzle header nozzle 9c Stirring nozzle P1 Drainage pump P2 Water supply pump P3 sand pump

Claims (3)

By injecting low pressure water to the bottom surface of the nozzle or al-precipitated sand pond flowing sediment deposited on the bottom surface thereof to the main runner, collect sediment of the main trough collector sand pit provided in the bottom of the sand basin low In the sand collection method ,
The nozzle is installed in the vicinity of the upper portion of the side wall in the sand basin, the water is placed in the sand collection pit so that the water surface of the sand basin is in the sand collection pit, and the nozzle is positioned above the water surface of the sand basin. the water from the nozzle is injected into the upper portion of the wall surface of the side wall, as well as washing the walls, to flow the sediment deposited on the bottom surface of the sand basin by the water flowing down the walls towards the main trough Sand collection method characterized by . 2. The sand collecting method according to claim 1, wherein the discharge amount of the nozzle is 0.15 to 0.3 m. ^Three A sand collecting method characterized by the fact that it is made per minute. Low pressure water is sprayed from the nozzle onto the bottom of the drained sand basin, and the sediment deposited on the bottom flows into the main trough, and the sediment from the main trough is collected in a sand collecting pit provided at the bottom of the sand basin. In the low pressure sand collection type sand collection device,
Nozzles attached at equal intervals to a nozzle header installed in the vicinity of the side wall of each region formed by dividing the bottom surface of the sand basin into a plurality of water flow directions in the sand basin, A sand collecting device, wherein the sand collecting device is attached so as to be injected at an incident angle of 15 to 60 degrees with respect to a wall surface .

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